An Experimental Investigation of R600a Condensation in a Multiport Microchannel.

Abstract

This study aims to provide condensation heat transfer coefficients of R600a (isobutane) refrigerant under mass fluxes between 50 and 98 kg/m2·s at saturation temperatures of 35 °C, 40 °C and 45 °C. Additionally, experiments are conducted with varying inlet vapour quality to understand its effect on the condensation heat transfer measurement. An aluminium multiport microchannel with a hydraulic diameter (Dh) of 0.399 mm is used, where a plexiglass cover is mounted on the top of the microchannels to observe the flow conditions. A 1D heat transfer through the aluminium block is assumed, and heat flux through the refrigerant to the coolant is measured to obtain condensation heat transfer coefficients of R600a. The results showed that decreasing saturation temperature and increasing vapour quality increase the condensation heat transfer coefficient. Increasing refrigerant mass flux increases the heat transfer coefficient up to a specific mass flux. It is observed that the effect of inlet vapour quality becomes significant as introduced quality decreases due to increasing fluctuation.